Yes, it is fairly easy just convert your book to a Word (.doc) document before uploading to Kindle or Nook. Both Amazon and Kindle have information on how to prepare your book for uploading. You can convert your PDF to Word on the Web site http://www.doc2pdf.net/PDF2Word/#convert but you will have to make sure everything is in place (no page number, breaks are correct etc).
When uploading to Amazon or Nook you can preview the book before publishing. I have published quite a few books on Amazon and Nook but not with iTunes yet.
To learn more read my Hub about publishing on Kindle